70Yellowbird

I found that the right half of the ‘bond beam’ headlight reinforcement has separated from the fiberglass body on my ’70. I have already carefully removed the entire bond beam w/o damaging it, and have removed the original rivets (and adhesive) that attach the steel section from the fiberglass piece, in order to prevent future issues with the rivets causing bumps in the body.

I would like to re-install the bond beam so it looks like original, though I would prefer to avoid using functional aluminum rivets as replacements. I’ve read many threads here on the Forum about the bond beam, but haven’t found anything yet that will help with a few specifics. I did mark the location of the bond beam so I can reinstall it at the original location. I have plenty of clamps to hold the beam while the adhesives are curing.

Here’s what I’d like to do, while asking for advice/guidance on my plan before going much further:

Install ‘functionally fake’ rivets where the original rivets were located, so the visible portion of the rivets have a similar appearance to the originals. I’m looking for ideas on how to do this; perhaps use non-aluminum rivets? Or can I coat (epoxy?) the aluminum rivets to avoid bi-metal corrosion with the steel section?

Use an appropriate adhesive to bond the fiberglass/steel section. I need to determine the metal prep/paint for the beam, based on what adhesive is needed. Recommendations?

Use appropriate adhesive to bond the beam assembly to the underside of the body. Recommendations/products/suppliers?

Thanks in advance for any help you can offer.

DUB

I have seen two different types of rivets that were used to rivet the fiberglass bonding strip to the steel support beam. One type was a tubular rivet and the other is a solid aluminum rivet.

When I do what out what to do...becasue I have done it many times....I leave the factory rivet in the steel beam. But seeing how you took them out...now you need to install and buck the rivet into the beam and try to get the bucked portion of the solid rivet to be like what GM had done.

Paragon sells the solid aluminum rivet that I would use if I had to but one back in due to the head is smaller in diameter that the ones that GM used that were kinda close to the diameter of a dime. The ones Paragon sells I would use have a diameter of the head about like that of an eraser of a #2 school pencil. I would make the diameter of this head of this rivet slightly small and when I bucked it into the beam. I would also apply some SEM 39747 adhesive so there would be a thin layer of it between the steel beam and the aluminum.

I would not be overly paranoid or concerned if I squeezed out the adhesive when I bucked the rivet. The reason being.. I have seen Corvettes that were never driven in the salt and the aluminum rivets that are seen on the underside of the car still look facotry perfect.

When salt is introduced to an area where aluminum and steel meet with NO barrier between them...that when things can go bad...but it also takes time.

I would use the SEM 39747 for all of your bonding and not look back. Call them so they can tell you how you need to prep the steel ...because...this product is epoxy based....so...they will want it rough BARE steel. Meaning...that when you apply it...as long as you have their product coating ALL bare steel...it can not rust. Getting a hold of the local area rep for SEM in your area..I am sure they will loan you the applicator gun needed. I am sure SEM has the name of your local rep. Or go by a local body shop and see if a guy has one that your can rent for a weekend.

The trick will be you grinding and routing out the areas in the fiberglass bonding strip so the heads of the rivets you reinstalled will not cause for an issue when you go to bond the steel beam the the fiberglass bonding strip.

Now if you are going to be concerned that any of this adhesive is going to ooze out and be seen when you raise your hood where the steel beam meet the fiberglas bonding strip...then that is when you will have to be inventive...because I can not give away all of my tricks.

Now there are other types of adhesive that will bond to a metal part that has been epoxy primed...and you can do a search for those...and I believe one of them is LORD FUSOR...but I can not remember the part number.

And if you go that route...meaning you want to prime the metal beam where the adhesive is going to be applied...you have to be careful that you do not get too much epoxy primer on the metal part in that area...because if you get to much on it (mil thickness)...the chances that it can shear is possible. So if you do this...soaking the part down in epoxy primer thinking that you are doing good...you actually are not

DUB